In a circuit device having a field effect transistor and a capacitor, the capacitor is connected to at least one of a gate electrode, a source electrode and a drain electrode of a field effect transistor, the field effect transistor has a channel comprised of a first nano-wire, and the capacitor comprises a first electrode comprised of a second nano-wire having electroconductivity, a dielectric layer partly covering the peripheral face of the first electrode and a second electrode covering the peripheral face of the dielectric layer.